Sun Bears on Borneo (Helarctos malayanus euryspilus) are sufficiently different from those on the Asian mainland and Sumatra, representing the typical form (H. m. malayanus), as to warrant subspecific differentiation (Meijaard 2004).

Justification:
Given the Sun Bear’s dependence on forest, it is clear that the large-scale deforestation that has occurred throughout southeast Asia over the past three decades has dramatically reduced suitable habitat for this species. Although quantitative data on population sizes or trends are lacking, it is suspected that the global population of Sun Bears has declined by > 30% over the past 30 years (3 bear generations). Deforestation has reduced both the area of occupancy (AOO) and extent of occurrence (EOO) of Sun Bears, and has also reduced habitat quality in remaining forest. In Malaysia and Indonesia, deforestation will likely continue as long as accessible forest areas with high value timber stock are available. This will result in a highly fragmented range for sun bears, with forest mainly conserved at higher altitudes where forest clearing and harvesting are either difficult or not economically viable.

In addition, Sun Bear numbers have been reduced by uncontrolled exploitation for body parts. It is expected that commercial exploitation will continue during the next 30 years unless abated by the implementation of significant anti-poaching measures.

Sun bears occur in mainland Southeast Asia as far west as Bangladesh and northeastern India (Chauhan 2006), as far north as southern Yunnan Province in China, and south and east to Sumatra and Borneo, respectively. It now occurs very patchily through much of its former range, and has been extirpated from many areas, especially in mainland southeast Asia. Its current distribution in eastern Myanmar and most of Yunnan is unknown. Reports of sun bears formerly occupying Nepal appear to be erroneous. Sun bear fossils from the Pleistocene have been found much further north into China and on the island of Java (Erdbrink 1953), but sun bears did not occur there in historical times.

Sun bears are uncommon at the northern and western edges of their range (southern Yunnan province, southeastern Tibet, northeast India, and Bangladesh; (Chauhan 2006, Gong and Harris 2006); this lower abundance was apparent in historical times (e.g., in India; Higgins 1932) so is probably a natural gradient unrelated to human exploitation.

Reliable estimates of sun bear populations are lacking. However, rapid loss of forests throughout their range and an active trade in wild bears and their parts is strong evidence of a declining trend. Attempts to extrapolate population size (e.g., Meijaard 2001) from anecdotal information on bear density (derived from occasional bear sightings and sign surveys, e.g. Davies and Payne 1981) have led to unreliable estimates (Garshelis 2002). Augeri (2005) used occupancy modeling (based on camera trapping) to estimate proportions of Indonesian Protected Areas that were occupied by sun bears. The proportion of an area occupied (occupancy) is likely correlated with population size, so finer-scale population trends might be gleaned from changes in occupancy.

Sun bears rely on tropical forest habitat. Two ecologically distinct categories of tropical forest occur within its range, distinguished by differences in climate, phenology, and floristic composition. Tropical evergreen rainforest is the sun bear’s main habitat in Borneo, Sumatra, and Peninsular Malaysia. This aseasonal habitat receives high annual rainfall that is relatively evenly distributed throughout the year. Tropical evergreen rainforest, includes a wide diversity of forest types used by sun bears, including lowland dipterocarp, peat swamp, freshwater swamp, limestone/karst hills, hill dipterocarp, and lower montane forest.

In contrast, sun bears in mainland Southeast Asia inhabit seasonal ecosystems with a long dry season (3–7 months), during which rainfall is <100 mm per month. Seasonal forest types are usually interspersed in a mosaic that includes semi-evergreen, mixed deciduous, dry dipterocarp (<1,000 m elevation), and montane evergreen forest (>1,000 m). The range of sun bears overlaps that of Asiatic black bears (Ursus thibetanus) in this seasonal forest mosaic.

Sun bears also have been reported in mangrove forest, although their occurrence in this forest type probably depends on proximity to other, more favored habitats. Sun bears use selectively logged areas (Wong et al. 2004, Meijaard et al. 2005), and oil palm plantations near forest edges (Nomura et al. 2004). However, there is no evidence that sun bears can survive in deforested or agricultural areas in the absence of nearby forest (Augeri 2005).

Sun bears occur from near sea level to over 2,100 m elevation, but appear to be most common in lower elevation forests. In Indonesia and western Thailand, for example, sun bears occur primarily below 1,200 m (Augeri 2005, Vinitpornsawan et al. 2006). Sun bears have been observed up to 2,100 m in Myanmar (Saw Htun 2006), 1,600 m in Lao PDR (Steinmetz et al. 1999), and 2,143 m in Sumatra (Augeri 2005).

Sun bears are omnivores, feeding primarily on termites, ants, beetle larvae, bee larvae and honey, and a large variety of fruit species, especially figs (Ficus spp.), when available (McConkey and Galetti 1999, Wong et al. 2002, Augeri 2005, Fredriksson et al. 2006). Occasionally, growth shoots of certain palms and some species of flowers are consumed (Fredriksson et al. 2006), but otherwise vegetative matter rarely occurs in the diet. In Bornean forests, fruits of the families Moraceae, Burseraceae and Myrtaceae make up more than 50% of the fruit diet (Fredriksson et al. 2006), whereas in western Thailand fruits of Lauraceae and Fagaceae are the most commonly consumed (Vinitpornsawan et al. 2006). In Thailand sun bears and Asiatic black bears use many of the same habitats and have extensive overlap in diet. However, in montane forests >1,200 m elevation (where ground cover is sparse) Asiatic black bears are more abundant than sun bears (Vinitpornsawan et al. 2006).

Little is known about social structure or reproduction in sun bears. Except for females with their offspring, sun bears are usually solitary. They may congregate to feed from large fruiting trees, but this behavior appears to be rare. Sun bears do not seem to have a defined breeding season anywhere in their range and usually give birth to only one cub (less commonly two; Schwarzenberger et al. 2004). Female bears use cavities of either standing or fallen large hollow trees as birthing sites. As sun bears occur in tropical regions with year-round available foods, they do not hibernate.

The two major threats to sun bears are habitat loss and commercial hunting. These threats are not evenly distributed throughout the range of the species. In areas where deforestation is actively occurring, sun bears are mainly threatened by the loss of forest habitat and forest degradation arising from: clear-cutting for plantation development, unsustainable logging practices (Augeri 2005, Meijaard et al. 2005, Tumbelaka and Fredriksson 2006, Wong 2006), illegal logging both within and outside protected areas (Fuller et al. 2004), and forest fires (Fredriksson et al. 2007). These threats are prevalent in Indonesia and Malaysia on the islands of Sumatra and Borneo (Sundaland), where large-scale conversion of forest to oil palm (Elaeis guineenis) or other cash crops is proceeding at the rate of 1,000s of km² per year (Holmes 2002).

Human-caused fires in parts of Sundaland are also diminishing habitat quality for sun bears. These fires are more extensive during El Niño-related droughts. On Borneo, periods of prolonged drought have disrupted fruiting patterns (e.g., Harrison 2000), which in combination with reduced habitat availability due to logging and fires, resulted in starvation among sun bears, even in primary forest areas (Wong et al. 2005, Fredriksson et al. 2006b).

Commercial poaching of bears for the wildlife trade is a considerable threat in most countries (Meijaard 1999, Nea and Nong 2006, Nguyen Xuan Dang 2006, Saw Htun 2006, Tumbelaka and Fredriksson 2006, Wong 2006), and is the main threat where deforestation is currently negligible (for example in Thailand where nearly all remaining forest is within protected areas; Vinitporsawan et al. 2006). Killing bears is illegal in all range countries but is largely uncontrolled. In Thailand, local hunters in one area estimated that commercial poaching reduced the abundance of sun bears by 50% in 20 years (Steinmetz et al. 2006).

In Myanmar, Thailand, Lao PDR, Cambodia and Viet Nam, sun bears are commonly poached for their gall bladders (i.e., bile) and bear-paws; the former is used as a Traditional Chinese Medicine, and the latter as an expensive delicacy. In China and Viet Nam, bile is milked from commercially-farmed bears; however, as there are few sun bears in China, farms there contain mainly Asiatic black bears. Conversely, both sun bears and Asiatic black bears are farmed in Viet Nam, in small private enterprises. Bears are routinely removed from the wild to stock or restock these small farms (Nguyen Xuan Dang 2006, B. Long, MOSAIC and WWF-Viet Nam pers. comm.).

Other motivations for killing bears include: preventing damage to crops (Fredriksson 2005), subsistence use, fear of bears near villages, and capture of cubs for pets (the mother being killed in the process). Although few sun bears exist in India, villagers there still kill sizeable numbers (Chauhan and Singh 2006).

Despite significant poaching within extant forest areas, sun bear populations appear to persist longer than some other heavily-exploited large carnivores. For example, tiger (Panthera tigris) populations have been severely reduced or extirpated in 12 of 15 protected areas surveyed in Myanmar, whereas sun bears were still encountered relatively frequently in 13 of these areas (Lynam 2003, Saw Htun 2006). Similarly, in Thailand tigers are close to extirpation in the Khao Yai forest complex, but sun bears and their signs are still consistently encountered there (Lynam et al. 2006, Vinitpornsawan et al. 2006).

Killing of sun bears is strictly prohibited under national wildlife protection laws throughout their range. However, little enforcement of these laws occurs. The sun bear has been listed on CITES Appendix I since 1979.

Conservation measures and priorities vary by country. None of the range countries have established specific conservation measures for sun bears, and some taking is permitted (Servheen 1999). General measures to reduce forest loss and poaching would help conserve the species. The most beneficial conservation measure in Indonesia and Malaysia would be protection of remaining forests from conversion to other land-uses, eliminating unsustainable logging practices, and prevention of forest fires. Establishment of new and effectively managed protected areas in Indonesia and Malaysia should be promoted in order to preempt land conversion (Augeri 2005, Tumbelaka and Fredriksson 2006, Wong 2006).

Reducing the trade in bear parts would be highly beneficial for the survival of the species in mainland Southeast Asia. However, given available resources, the patrolling and monitoring of entire protected areas is currently an overwhelming task. To make this problem more manageable, a network of small bear recovery zones (100–200 km²) could be established within key protected areas. The patrolling efforts of rangers could then be focused on these zones. Recovery zones should be locations with plentiful bear foods such as trees from the families Lauraceae, Moraceae, Burseraceae, Myrtaceae and Fagaceae. Such zones would provide a biologically meaningful, geographically focused, and logistically realistic way for the efforts of protected area staff to be translated into population recovery for bears (and other wildlife species).

Recently, the Bear Specialist Group mapped the current, range-wide distribution of sun bears. Important habitat blocks for long-term survival of sun bears were identified (Bear Conservation Units-BCUs). Anti-poaching efforts within these BCUs should be a high priority. Trends in bear occurrence and relative abundance within BCUs could be monitored using standardized sign surveys and camera trapping. Results of such monitoring could indicate which management or ecological conditions promote successful bear conservation, and which do not, and provide a means to assess the results of conservation efforts (e.g., future range expansion and/or increased bear density being indicative of effective conservation efforts). Additional field studies also would be helpful in this regard; few intensive studies have been conducted on this species.